Fletcher was fortunate enough to play in two finals at Wembley last season and scored in both games while he was on loan at Barnsley.
The talented forward got his name on the scoresheet in the Johnstone's Paint Trophy Final against Oxford and returned a month later when he scored the opening goal in the League One Play-Off Final win over Millwall which saw his side gain promotion into the Championship.
With the Hammers facing a big EFL Cup quarter-final tie against Fletcher's former club Manchester United on Wednesday night, the 21-year-old is now hoping play to his part once again and win another piece of silverware.
Fletcher said: “I have got special memories of playing at Wembley. For me to get there a third time, especially for West Ham in such a big game, would just be unbelievable.
“If we play like we did on Sunday then we have a big chance of winning the game.
“Any cup run is important because if you win the competition, the confidence can only help you in other games.
“We had a similar thing at Barnsley last season after winning the Johnstone's Paint Trophy because we then went back for the Play-Off Final and it wasn't a problem for us because we had been there before and didn't have any nerves.
“It gives you the platform to move forward in the season and do well.”
Fletcher will be making another emotional return to Old Trafford on Wednesday night after coming through the youth ranks at Manchester United.
The Hammers striker will once again have a number of friends and family watching from the stands and he hopes to go one better after having a great chance to win the game for West Ham on Sunday, but fired his shot straight at David de Gea during the 1-1 draw.
With Diafra Sakho ruled out for six weeks with a thigh injury, Fletcher says he is ready to take his chance if Slaven Bilic names him in the starting line-up.
Fletcher added: “It was one of those chances that if I had hit the ball either side of De Gea, the ball would have gone in, but the angle I found myself in, I could only strike the ball straight at him.
“I will have a lot of family and friends watching once again so hopefully I can put a chance away in this game!
“I couldn’t have asked for anything better since I joined West Ham. I came thinking that I would hopefully be a player for the future but that if I impressed I would get my chance.
“I scored a few goals in pre-season and the manager, Slaven Bilic said, ‘You’re not going anywhere. I want you to stay with us and be part of the senior squad.’
“That was a huge confidence booster for me and since then I believe I’ve been involved in every match-day squad except the first one against Chelsea."
Tickets are still available for the game on Wednesday night. Fans should visit the ticketing and membership services office at Old Trafford which is open from 8am on Wednesday.